Generally, in disc brakes, the brake caliper is arranged astride of the outer peripheral edge of a brake disc. The brake caliper usually comprises a body having two elongated elements, called side portions, which are arranged so as to face opposite braking surfaces of a disc. Between each side portion of the caliper and the braking surfaces of the brake disc, friction pads are provided. At least one of the side portions of the body of the caliper has cylinders suitable for receiving pistons, actuated in any suitable known way (for example hydraulic or electric pistons), capable of exerting a thrusting action on the pads, abutting them against the braking surfaces of the disc to exert a braking action on the vehicle.
The brake calipers are usually fixedly connected to a support structure that stays fixed to the vehicle, such as for example an axle-journal of a vehicle's suspension.
In a typical arrangement, one of the two side portions has two or more attachment portions of the body of the caliper to the bearing structure, for example by providing slots or eyelets, for example arranged axially, or through holes, for example arranged radially, suitable for receiving screws for the attachment of the caliper that, with their ends, are received in threaded holes provided on the bearing of the caliper.
Such a side portion is called attachment side portion.
The other portion is called non-attachment side portion.
In a typical construction of a caliper body, the side portions facing the braking surfaces of the disc are connected together by bridge elements arranged astride of the disc and called bridges.
Generally, a caliper body is made mainly from aluminium.
Such a material is satisfying from the point of view of resistance to stress and rigidity, however aluminium caliper bodies have a high weight.
As it is well-known, a caliper body with a high weight constitutes a serious drawback for different reasons, including the performance of the vehicle on which it is applied and the braking efficiency.
Such drawbacks are even worse in the case of racing vehicles, for which weight-reduction is essential.
In order to obtain a caliper body that, apart from achieving sufficient rigidity and resistance to stress, has also a low weight, different solutions have been studied.
For example, the patent application published with No. GB 2 087 490 discloses a caliper for a disc brake made from aluminium that comprises a steel or titanium insert.
The patent application published with No. DE 196 47 999 discloses an aluminium caliper provided with a reinforcement made from composite material having a metallic matrix.
European patent No. EP 0 725 697 discloses a method for producing a caliper that provides the moulding of a bridge and of an outer portion of an arm and in which an insert made from iron alloy is used.
The US patent application published with No. US 2010/0038190 discloses a caliper obtained by moulding with a light metal or an alloy thereof, which comprises a structure made from iron or an alloy thereof.
The aforementioned known solutions, although they achieve the desired mechanical strength and rigidity, do not achieve satisfying advantages in terms of weight reduction.